Tripod type constant velocity joint

Abstract

A constant velocity joint of a tripod type comprising a housing formed with three recesses having first and second guide grooves each extending axially in the housing, a tripod comprising trunnions with a bearing assembly having an inner roller and an outer roller in a rolling contact relationship and the first and second guide grooves formed such that the outer roller is tightly pressed on the first guide groove when a rotating force is transmitted, and that the axis of each of the trunnions is displaced from a parallel relationship with the flat bottom face of the first guide groove when the outer roller is pressed thereon with the joint angle kept zero.

What is claimed is:  
     
       1. A constant velocity joint of a tripod type comprising: 
       a hollow cylindrical housing to be connected to a first rotating shaft,  
       a tripod contained in the housing so as to be connected to a second rotating shaft,  
       the first rotating shaft having a joint angle relationship with the second rotating shaft,  
       the housing having an inner peripheral surface formed with three recesses spaced apart from each other in a circumferential direction with a uniform space therebetween,  
       each of the recesses having an inner surface formed with first and second guide grooves each extending axially in the housing and having a flat bottom face,  
       the tripod including a base portion through which the tripod is connected to the second rotating shaft, three trunnions with an axis each having a first end connected to the base portion and a second end extending to one of the recesses, and a bearing assembly mounted to the second end of each of the trunnions,  
       the bearing assembly having an inner roller provided concentric with each of the trunnions and having an inner peripheral face and an outer peripheral face, so that the inner roller is rotatable around the trunnion, and an outer roller fitted around the inner roller and having a short-cylindrical outer peripheral face, an outer side face portion adjacent the outer peripheral face and an inner peripheral face, the outer peripheral face and side face portion of the outer roller received in the first and second guide grooves in the recess so that the outer roller is placed in a rolling contact relationship with the first and second guide grooves so as to be moved only axially in the housing, and the inner peripheral face of the other roller engaged with the outer peripheral face of the inner roller, so that the outer roller has a rocking relationship with the inner roller,  
       the first and second guide grooves formed such that the outer peripheral face of the outer roller is pressed on the first guide groove with a clearance formed generally between the outer peripheral face and side face portion of the outer roller and the second guide groove when rotating force is transmitted through the first and second rotating shafts, and  
       that the axis of each of the trunnions is displaced from a parallel relationship with the flat bottom face of the first guide groove when the outer roller is pressed on the first guide groove with the joint angle between the first and second rotating shafts kept zero.  
     
     
       2. The constant velocity joint of claim  1 ; wherein the flat bottom face of the guide grooves is inclined at an angle between 1.5 to 3.5 degrees with reference to the axis of the trunnion. 
     
     
       3. The constant velocity joint of claim  1 ; wherein each of the inner rollers is supported by the trunnion with a plurality of needle bearings therebetween so as to be rotatable around the trunnion and movable axially along the trunnion, the inner roller has a spherical convex outer peripheral surface while the outer roller has a spherical concave inner peripheral surface to mate the spherical convex outer surface, so that the outer roller is supported by the inner roller in a rocking member.